This application claims the benefit of Korean Application No. 2002-31109 filed Jun. 3, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to control of a logistics system, and more particularly to a method of predicting a carrying time in an automatic warehouse system which functions as a buffer in a logistics system.
2. Description of the Related Art
FIG. 1 is a block diagram of a logistics control system of a typical semiconductor production line. As shown in FIG. 1, a production control system 102 receives process data from a semiconductor production line 108, generates carrying commands for parts required for a current process or carrying commands for products having completed a process and transmits the carrying commands to a logistics control system 104. The logistics control system 104 transmits a control command to an automatic warehouse system 106, such that a carrying operation can be performed between the semiconductor production line 108 and the automatic warehouse system 106. The control commands can comprise factors that influence a carrying time, such as a carrying type, operation priority, etc. In this case, logistics data are provided from the automatic warehouse system 106 to the logistics control system 104.
In industry fields such as a semiconductor manufacturing process, logistics control, which is used to provide parts required by a production line or to carry and load processed products in the production line, is a very important part in shortening a production period. That is, if a time required for a carrying operation is shortened by selecting a carrying path requiring a shortest carrying time, an entire production period of a product can be shortened. Therefore, it is desirable to shorten production periods of products so as to reduce production costs of products.
Accordingly, the present invention has been made keeping in mind at least the above problems occurring in the related art, and the present invention provides a method of predicting a carrying time in an automatic warehouse system using a neural network, which calculates a predicted (i.e., an optimal) moving (carrying) coefficient (i.e., a virtual moving coefficient) by modeling an automatic warehouse system using a neural networks theory, and selects an optimal carrying path for a carrying command of a production control system by applying the predicted moving coefficient to a real logistics control system.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The present invention may be achieved by a method of controlling an automatic warehouse system in a logistics system, comprising setting input variables of the automatic warehouse system to a virtual automatic warehouse system modeling the automatic warehouse system based upon the input variables; setting an optimal weighting value according to the modeling; calculating a predicted carrying time based upon the optimal weighting value, input data corresponding to the input variables and past history data related to a moving time(s) in the automatic warehouse system; calculating an error between the predicted carrying time and a real carrying time in the automatic warehouse system; and selecting an optimal carrying path in the automatic warehouse system according to the predicted carrying time if the error is within a preset allowable range.